CCPM

Cyclic/Collective Pitch Mixing — Aileron, Elevator, and Collective are combined to give helicopter swash plate servo commands.  Required for control of most modern RC helicopters that use a flybar.  See also CPPM.

Chop Throttle

A term used by RC helicopter pilots describing rapid reduction of throttle stick setting on the Tx.  A habit often formed with fixed pitch or coaxial helicopters that can destroy fixed pitch helicopters by driving them into the ground

Collective

Collective is the angle of the main rotor blades of a heli and is why a collecive pitch helicopter can fly upside down. Helicopters with fixed pitch blades (this includes almost all coaxial helicopters) do not require collective.

CPPM

Combined Pulse Position Modulation — Allows two functions (cyclic and collective pitch mixing) to drive three servos for the swash plate of a helicopter.  See also CCPM.

CYC(x)

CYC1, CYC2, CYC3 describe the OpenTX outputs for CCPM mixing for direct control of servos on the swash plate of a helicopter.  Inputs are Aileron, Elevator, and Collective.